On the character of the melting transition in small atomic aggregates

Abstract

The melting transition in small clusters of N atoms is investigated, using a biased random walk, Monte Carlo procedure. A high density of data points, with small statistical uncertainities (about 0.3%) is generated near the melting transitions T m (N). The results show an abrupt change in physical properties near melting, but there is no evidence that the transition is either first or second order in character. Rather, the transition is more gradual. The T m (N) for N=13, 11, 8, and 6 are 28.75, 20.0, 10.2, and 9.6K, respectively. N=6 and 8 evaporate at T B ?31 K. The low temperature structures are dynamically determined to be octahedron, pentagonal bipyramid plus one, pentagonal bipyramid plus four, and icosahedron, for N=6, 8, 11, and 13, respectively.